With development of science and technology, a server has been provided with a lot of functions. Due to a limited area of a PCB (Printed Circuit Board), reserved positions on the PCB for some different interfaces are required to be overlapped one to another, in order to achieve versatility of the server.
By reserving positions for different interfaces on the PCB in an overlapped manner, the PCB may be configured to have a type of interface when required, and changed to have another type of interface when requirement is changed. In this way, less number of types of mainboard are required in one aspect, and developing costs can be greatly reduced in another aspect.
However, it is difficult to design reserved overlapping position for an optical interface and an electrical interface, because generated radiation of EMI (Electro Magnetic Interference) is different due to different operating frequencies of the optical interface and the electrical interface. In a case that EMI radiation in using one interface meets requirements, the EMI radiation in using the other interface cannot meet the requirements. Therefore, the reuse of reserved overlapping position for the optical interface and the electrical interface is hard to be achieved at present.